Apparatus for incremental movement of die frame

ABSTRACT

Apparatus for moving a frame of the type for supporting a plurality of integrated circuit chips or die members wherein the frame on a track is moved incrementally along the same by one or both of a pair of panels pivotally mounted below the track and normally projecting through the plane of the track and into openings in the frame. A reciprocal drive means coupled to the pawls causes the latter to reciprocate, so that the pawls, as they moves in reverse, pivot downwardly in the frame and into second frame openings, whereupon the pawls are urged forwardly and they, in turn, advance the frame through a predetermined distance. If the apparatus is used as a die bonder, an improved heat shield is provided for the heater element. Also, an improved die holder is disposed adjacent to and above the heater element. If the apparatus is used as a die test unit, an improved test probe is provided wherein test leads move in engagement with terminals of a die after the die frame has been incrementally advanced.

United States Patent [191 Diepeveen [451 Oct. 8, 1974 1 APPARATUS FORINCREMENTAL MOVEMENT OF DIE FRAME [76] Inventor: John C. Diepeveen, 1737Kimberley Dr., Sunnyvale, Calif. 94087 [22] Filed: Oct. 13, 1972 [21]Appl. No.: 297,506

Primary Examiner-Richard A. Schacher [57] ABSTRACT Apparatus for movinga frame of the type for supporting a plurality of integrated circuitchips or die members wherein the frame on a track is moved incrementallyalong the same by one or both of a pair of panels pivotally mountedbelow the track and normally projecting through the plane of the trackand into openings in the frame. A reciprocal drive means coupled to thepawls causes the latter to reciprocate, so that the pawls, as they movesin reverse, pivot downwardly in the frame and into second frameopenings, whereupon the pawls are urged forwardly and they, in turn,advance the frame through a predetermined distance. If the apparatus isused as a die bonder, an improved heat shield is provided for the heaterelement. Also, an improved die holder is disposed adjacent to and abovethe heater element. If the apparatus is used as a die test unit, animproved test probe is provided wherein test leads move in engagementwith terminals of a die after the die frame has been incrementallyadvanced.

' 14 Claims, 15 Drawing Figures Pmmwflm 8m 3.840.163.

sum nor 4 11 W m V1 STOP I l J I y// V MOTOR: SWITCH {ENERGI ZED l I I rThis invention relates to improvements in the handling of die supportframes and, more particularly, to apparatus for incrementally moving adie support frame past a die-handling area, such as is used in diebonding, wire bonding and die testing operations.

The present invention is suitable for use in incrementally advancing adie support frame along a predetermined path so that a plurality of diemembers or integrated circuit chips can be successively bonded torespective locations on the frame when the apparatus is used as a diebonder, or leads can be bonded to die members previously bonded to theframe if the apparatus is used as a wire bonder. Moreover, theincremental advancement of the frame can be utilized in the testing ofdie members bonded to the frame if the apparatus is to be used as a testprobe unit. In all such uses, a die frame is moved incrementally byimproved, reciprocal pawl means such as a pair of spaced pawls whichmove out of engagement as the pawl means reverses but move intoengagement with and advance the frame as the pawl means moves forwardly.

The pawls are carried by a reciprocal rod below the path of movement ofthe frame and the frame itself is generally provided with a grid ornetwork of spaced, metallic terminal strips or spaced sprocket holes atthe side margins thereof, whereby the pawls can enter the spaces betweenthe strips or enter the holes so as to engage the frame for moving thesame forwardly. The pawls normally project through a frame support platedefining a track along which the frame is moved. Each pawl has a rearinclined margin so that, as the pawl is reversed, it is forceddownwardly and out of a space or hole of the frame and into a rearwardposition at which it is in vertical alignment with the next adjacentspace or hole, whereupon bias means coupled with the pawl urges itupwardly and into such aligned space or hole. Then the pawl is urgedforwardly, and the pawl thereby engages and advances the frame until thenext die support location is in an operative position.

Means for reciprocating the rod includes a rotatable eccentric coupledto a stepper motor. The eccentric also operates a pivotal frame clampwhich holds the frame against movement during a die handling operation,such as a die bonding step.

The present invention includes an improved heat shield around the heaterelement of the apparatus when the latter is used as a die bonder. Theshield has tubular support posts providing a chimney effect fordirecting cool air from beneath the apparatus to a region near theheater element, thereby causing the heat therefrom to rise to the diesupport of the frame thereabove. Also, the shield prevents adjacentstructure from being heated by reflecting the heat radiated by theheater element. Thus, the heat is localized so that injuries to thefingers or hand of the operator of the apparatus will be avoided.

The primary object of this invention is to provide an improved apparatusfor advancing a die support frame wherein a pivotally mounted pawlprojecting through the frame is reciprocated and urges the frameforwardly an incremental distance after each reversal of the pawl, yetthe frame is stationary during pawl reversal to thereby assure movementof the frame in only one direction.

Another object of this invention is to provide apparatus of the typedescribed wherein the'pawl is caused to pivot downwardly below and tomove along and beneath the frame during pawl reversal but, thereafter,the pawl pivots upwardly and extends through the frame and duringforward pawl movement, advances the frame through an incrementaldistance sufficient to move the next adjacent die support of the frameinto an operative position at which a die handling operation can occur.

Other objects of this invention will become apparent as the followingspecification progresses, reference being had to the accompanyingdrawings for an illustration of the invention.

FIG. 1 is a perspective view of the apparatus of this invention;

FIG. 2 is an enlarged, top plan view of the apparatus;

FIG. 2a is an enlarged, fragmentary, side elevational view of the heaterassembly of the apparatus when the same is used as a ,die bonder;

FIG. 3 is a bottom plan view of the apparatus, parts I being broken awayto illustrate details of construction;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a cross-sectional view taken along line 55 of FIG. 2;

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 2;

FIG. 7 is a cross-sectional view taken along line 7-7 of FIG. 1; r

FIG. 8 is an enlarged, fragmentary, vertical, crosssectional view of theapparatus, showing a framemoving pawl thereof;

FIG. 9 is a fragmentary, side elevational view of the die support abovethe frame-supporting surface of the apparatus;

FIG. 10 is a fragmentary, top plan view of a test unit on the apparatuswhen the latter is used to test semiconductor components;

FIG. 10a is an end elevational view of the test unit;

FIG. 11 is an enlargedv vertical cross-section of the mechanism forraising or lowering the frame clamp finger of the apparatus;

FIG. 11a is a top plan view of a part of the mechanism of FIG. 11; and

FIG. 12 is a timing diagram showing the sequence of operation of theapparatus.

The apparatus of this invention is broadly denoted by the numeral 10 andincludes a support 12 comprised of a pair of opposed sidewalls l4 and 16and a pair of opposed end walls 18 and 20. A generally horizontal plate22 is mounted on walls 14, l6, l8 and 20 and covers the open upper end'of the space surrounded by such walls. Thus, the side and end walls andthe top plate define a hollow housing.

Plate 22 is provided with a rail or first bar 24 (FIGS. 1, 2, 4, 5 and6) along one side margin thereof and a pair of spaced second rails orbars 26 and 29 (FIGS. 1, 2, 4, 6 and 7) along the opposite side marginthereof. Bars 24, 26 and 28 are adjustably mounted on plate 22 by screws29, each bar having a slot-shaped, screwreceiving hole as shown in FIG.2. The bars have cross sections of the type shown in FIGS. 4-6 whereineach of the bars has a lateral projection portion 30 (FIG. 4)

which overlies and is spaced above the upper surface 32 of plate 22.Thus, plate 22 and bar portions 30 define a track 31 (FIGS. 4-6)extending longitudinally of the plate in substantial spanningrelationship to end walls 18 and 20, the track adapted to receive andguide a generally rigid, metallic die support frame 34 (FIG. 2) of thetype for supporting a plurality of integrated circuit chips or the like.Bars 24, 26 and 28 are open at their outer ends so that frame 34 can bemanually placed on track 31 at its entrance end (the right end of plate22 when viewing FIG. 2) and can leave the track at the exit end thereof.

Frame 34, for purposes of illustration, has a pair of opposed, parallelside strips 36 (FIG. 2), a central strip 38 parallel to side strips 36,and a plurality of spaced lateral strips 40 which interconnect centralstrip 38 with respective side strips 36. Side strips 36 are providedwith a plurality of holes 42 therethrough much in the same manner as inphotographic movie film. Central strip 38 is adapted to support aplurality of integrated circuit chips or other semiconductor componentsat spaced locations thereon, specifically in alignment with respectivelateral strips 40,.the strips serving as leads for terminal points onthe chips supported on central strip 38. Frame 34 is of conventionalconstruction and may or may not have openings 42. Other types ofchip-supporting frames can be used with apparatus 10, such as thosehaving no holes corresponding to holes 42 and those having a pluralityof leads or lateral strips for each chip locations, respectively.

The purpose of apparatus 10 is to advance frame 34 incrementally alongtrack 31 so that the various chip or die locations on central strip 38are successively moved into overlying relationship with an opening 44(FIGS. 1, 2 and in plate 22. For purposes of illustration, apparatus isshown in FIGS. 1-9 as a die bonding machine wherein strip 38 is movedincrementally over and past a die bonding heater element 46 (FIGS. 1, 2,4 and 5) aligned with opening 44 of plate 22. The apparatus could alsobe used for wire bonding operations wherein a wire bonder carried bysupport 12 could be used to bond wires to a plurality of spaced chips ona chipsupporting frame which is supported from beneath on a surfacedisposed in opening 44. In such a case, heater element 46 would beremoved to make room for the support surface. Furthermore, a test probeunit 49 (FIGS. 10 and 100) can be substituted for heater element 46 sothat apparatus 10 can be used in the electrical testing of integratedcircuit chips as they incrementally advance on frame 34.

The means for incrementally moving frame 34 in-' cludes a pair of spacedpawls 50 and 52 (FIGS. 4, 5, and 7 and 8), each pawl comprising a rigidbar 54 which is pivotally mounted by a pin 55 on the upper end of afollower 56 disposed below plate 22 (FIGS. 4, 5 and 7). Each bar 54 hasa forward edge or margin 58 which is generally perpendicular to track 31when bar 54 is in its operative position (the full-line. position ofFIG. 7), i.c.. the position at which it moves frame 34 forwardly (to theleft when viewing FIG. 2). The rear edge or margin 60 is inclined andconvergent to margin 58 so that margins 58 and 60 define a pointed upperend 61 on bar 54.

A counterweight 62 is adjustably and eccentrically mounted by a screw 64on the lower end of each bar 54, respectively. This counterweight biasesthe corresponding bar in a clockwise sense when viewing FIGS.

7 and 8, yet allows the bar to pivot into its retracted position (thedashed-line position of FIG. 7). The counterweight also engages surface65 of follower 56 so that surface 65 serves as a stop to limit theupward movement of upper end 61 of each pawl. The height Ii (FIG. 8) ofupper end 61 relative to the upper surface 32 of plate 22 can beadjusted by adjusting the position of counterweight 62 with respect topin 64. Thus, by rotating the counterweight relative to its bar 54 intoa new, fixed position, the value of It will change.

Plate 22 has a pair of slots 66 and 68 therethrough in the plane ofrespective bars 26 and 28 (FIGS. 1, 7 and 8) and disposed below the pathof one of the side members 36 of frame 34. These slots are adapted topermit respective pawls 50 and 52 to extend upwardly and through plate22 so that upper ends 61 of the pawls project above upper surface 32 ofplate 22. Thus, upper ends 61 can enter respective, aligned sideopendings 42 in frame 34 so that the pawls, in their operative positions(FIG. 8), can push the frame incrementally forwardly as the pawls areshifted incrementally to the left when viewing FIGS. 7 and 8. A pair ofspring fingers 70 and 72 overlie respective slots 66 and 68 and serve tohold frame 34 in a fixed position on track 31 as the pawls retract andmove rearwardly in a manner to be described.

Followers 56 (FIGS. 3, 4, 5 and 7) are rigidly secured to a first rod 74which extends longitudinally of track 31 and is shiftably mounted forlongitudinal movement in a pair of bearing blocks 76 and 78 (FIGS. 3 and7) rigidly secured to the lower surface 82 of plate 22. A screw (FIG. 5)adjustably clamps each follower 56 to rod 74, whereby the position ofthe corresponding pawl can be adjusted relative to its slot throughplate 22. Each follower 56 has a lower extension 84 (FIGS. 4 and 5)having a side surface 86 normally slidably engaging one side ofa second,fixed rod 88 parallel to rod 74 and end walls 18 and 20 in spanningrelationship thereto. Rod 88 serves as a guide for followers 56.

A coupling element 90 (FIGS. 6 and 7) is secured to first rod 74 anddepends therefrom. Element 90 has a vertically disposed channel 92(FIGS. 6) for shiftably receiving a cylindrical roller 94 eccentricallymounted on a disk 96 having a cylindrical base 98 secured to the driveshaft 100 of a stepper motor 102 rigid to and extending laterally fromsidewall 16 (FIGS. 3, 4, 5 and 6). Roller 94 operates to causehorizontal reciprocation of element 90 relative to and along rod 88. Asshown in FIG. 7,'the axis of roller 94 is spaced laterally from the axis97 of disk 96. As the disk is rotated under the influence of steppermotor 102 through a complete revolution, roller 94 rotates about axis 97and, as it does, it moves element 90 from a starting position first tothe right (when viewing FIG. 7) through a first distance, and then backto the left through the first distance, and beyond through a seconddistance, and then back to the right through the second distance to itsstarting position. When element 90 is reciprocated, it causes rod 84 toreciprocate and this, in turn, causes reciprocation of followers 56 andrespective pawls 50 and 52.

In FIG. 7, element 90 is shown at its extreme lefthand position, justbefore it is returned to the right to its starting position. Whenelement 90 is in its starting position, pawls 50 and 52 are tilted moreto the horizontal as shown by the dashed line positions thereof in FIG.7. This is because frame 34 will cause the pawls to rock in acounterclockwise sense and out of respective frame holes, yet willremain in respective slots 66 and 68 as element 90 is returned to itsstarting position. The pawls, in their starting positions, are half-waybetween the holes they have just left and the holes they will nextenter. A switch 940 (FIG. 7) coupled with disk 94 stops motor 102 whenelement 90 returns to its starting position. An override circuit coupledwith motor 102 actuates the same at the beginning of a frame-movingoperation.

As the pawls are shifted to the right when viewing FIGS. 7 and 8 fromtheir starting positions, they will be moved through a distancesufficient to permit the upper end 61 of each pawl to be aligned withthe next adjacent hole 42, whereupon the bias action of thecorresponding counterweight 62 will cause the upper end 61 of the pawlto enter the aligned hole thereabove. Upon movement of each pawl to theleft, its front margin 58 will engage the frame and advance itincrementally to the left, thereby moving the next die support ofcentral strip 38 into overlying relationship to the central portion ofopening 44. Then, the pawls are returned to their starting positions aselement 90 is moved a short distance to the right as described above.While a pair of pawls have been shown, only a single pawl can be used tomove the frame. However, two pawls are provided on opposite sides ofopening 44 so that at least one pawl is in driving engagement with theframe at all times.

A frame clamp finger 104 (FIGS. 1, 2, 4 and 5) is provided for apparatus10 when the latter is to be used as a die bonder. Finger 104 extendsacross a portion of upper surface 32 of plate 22 and terminates adjacentto opening 44 as shown in FIG. 2. Finger 104 clamps the frame againstmovement relative to surface 32 as the pawls are reversed (shifted tothe right when viewing FIG. 7), i.e., as each pawl moves out of one hole42 and into alignment with the next adjacent hole 42. In this way, thepawls are assured of moving into the next pair of adjacent holes 42 toprovide for positive forward incremental movement of frame 34.

Finger 104 is secured by screws 106 (FIGS. 2) to a first block 108pivotally mounted by a pin 110 (FIG. 1) on a second block 112 adjustablysecured by screws 114 (FIG. 5) to the outer surface of sidewall 16, theholes in block 112 for screws 114 being enlarged to provide for theadjustability of the block in the x-y direction. In this way, theinclination of the finger can be adjusted, if necessary, to render thefinger parallel to the upper surface of heater element 46. A pair oflaterally projecting pins 116 at opposed sides of block 108 are coupledto the upper ends of a pair of coil springs 118 which extend downwardlyadjacent to the inner surface of sidewall 16 and are secured toprojections 120 (FIG. 7) on the inner surface of sidewall 16. Thesprings are under tension so that finger 104 is biased downwardly towardsurface 32. A third spring 122 (FIG. 7) is coupled at its upperend toblock 108 and at its lower end to a bar 124 pivotally mounted on acrossbrace 126 (FIG. 7) by a pin 128 which is horizontally disposed.Brace 126 is rigid to and spans the distance between sidewalls 14 and16. Spring 122 is under tension; thus, bar 124 is biased by spring 122in a counterclockwise sense when viewing FIG. 7.

A vertical rod 130 spans the distance between block 108 and bar 124 andis pivotal relative thereto as shown in FIG. 11. Both ends of rod 130are convex, the upper end being pivotally received in a conical recess131 in block 108 and the lower end being pivotally received in a conicalrecess 133 in a shiftable member 135 adjustably secured by a screw 132to bar 124 (FIGS. 11 and 11a).

The opposite end of bar 124 has a roller 138 which engages the outerperiphery 140 of disk 94 during movement of the pawls. During such pawlmovement, finger 104 is slightly spaced above opening 44, therebyallowing frame 34 to move beneath finger 104 and across the heaterelement 46. However, disk 96 has a flat, outer peripheral segment 142(FIG. 7) which moves into overlying relationship to roller 138 aselement returns to its starting position after each incremental framemovement. When this occurs, bar 124 is allowed to rotate through a smallarc in a clockwise sense (FIG. 7) about pin 128, causing the outer endof finger 104 to again engage frame 34 and clamp it to heater element46.

Roller 138 normally does not engage flat segment 142 because the outerend of finger 104 engages frame 34, before this occurs. Also, theinclination of finger 104 can be adjusted by the adjustment of theheight of rod by manipulating the height of member to accommodate bentframes or chips of different heights. Thus, the apparatus is suitablefor use in wire bonding operations as well as die bonding operations.The outer end of finger 104 has a central hole 105 therethrough toprovide access to the diesupport of frame 34 or to v a die on such diesupport. I

In FIG. 2a, a transversely U-shaped heat shield is provided to localizethe radiant and conducted heat from heater element 46. Shield 150 has 'apair of opposed sides 152 (FIG. 4) and a bottom 154. It is open at theends and at the top and is loosely supported by respective cotter pins164 (FIGS. 2a and 3) on a pair of tubular posts 156 which are adjustablysecured to and extend upwardly from a mounting bracket 158 secured byscrews 160 to a bar 162 (FIG. 3) which is rigid to and spans thedistance between the end walls 18 and 20. Cotter pins 164 pass throughholes in respective posts 156. Bracket 158 has a pair of clamping screws165 which adjustably secure the lower ends of posts 156 to bracket 158,thereby permitting the height of heater element 46 relative to opening44 to be varied.

I-Ieat shield 150 is formed of thin, polished, stainless steel andreflects heat radiated thereto by heater ele ment 46. Also, the looseconnection of the heat shield on posts 156 minimizes heat losesto theposts by conduction.

The upper and lower ends of each post 156 are open as shown in FIG. 2a,the upper end of each post being secured to a lateral extension 166(FIGS. 2a) of heater 46. The lower, open end of each post 156 is invertical alignment with a respective opening 168 through bar 162, sothat posts 156 operate as chimneys to direct cooling air from a locationbelow bar 162 to the regions on opposed sides of heater element 46. Thelower surface 169 (FIG. 2a) of heater element 46 is spaced above bottom154 of heat shield 150 by a distance equal to the spacing between heaterelement 46 and each side 152 of the heat shield. This construction ofthe heat shield localizes the heat radiated from heater element so thatthe person using apparatus 10 will not suffer burns to the fingers andhand during die bonding operations.

A swingable rod 170 (FIGS. 1, 2, 4, 5, 6 and 7) is swingably mounted onsupport 12 for movement through a small arc in a plane above andsubstantially parallel with the plane of plate 22. Rod 170 has a bracket172 (FIG. 9) clamped thereto by a screw 174. A stub shaft 176 isrotatably mounted in bracket 172 and has a knob 178 at its upper end. Adisk 180 having an annular base 182 thereabove is secured to the lowerend of shaft 176 so that, when knob 178 is rotated, disk 180 rotatesrelative to rod 170.

The upper, annular surface 184 of disk 180 operates to support aplurality of integrated circuit chips 186 to be bonded to frame 34 oncentral strip 38 thereof. Rod 170 is mounted so that, when it is swungin a counterclockwise sense when viewing FIG. 2, the chips on surface184 are moved into proximity to opening 44. Thus, the operator ofapparatus 10 can continue to view a chip-supporting location of frame 34aligned with heater element 46 through a microscope as the outerperipheral margin of disk upper surface 184 is moved into a part of theoptical path of the microscope, thereby permitting the operator totransfer a chip from surface 184 onto frame 34 without moving the headaway from the microscope. This will facilitate a die bonding operationand make such operation less tedious for the operator.

Rod 170 has a vertical leg 186 (FIGS. 1, 4, and 7) pivotally mounted-ina lateral extension 188 rigid to and extending outwardly from sidewall16. Leg 186 has a short bar 190 rigid to it and extending towardsidewall 16. Bar 190 has a hole 192 therethrough which receives a pin194 secured to and extending upwardly from extension 188, pin 194serving as a stop to limit the swinging movement of rod 170. A coilspring 196 coupled to extension 188 and bar 190 biases rod 170 in aclockwise sense when viewing FIG. 2.

OPERATION Apparatus is used by first manually placing frame 34 at theentrance end (the right-hand end when viewing FIG. 2) of track 31. Theframe is then manually moved along the track until the left-hand end ofstrip 38 is adjacent to heater element 46. Then, assuming heater 46 isenergized so that it is at a pre-determined operating temperature,stepper motor 102 is actuated so that it causes the pawls to reciprocatein the manner described.

As disk 96 rotates through a single revolution, the pawls move to theright below the plane of upper surface 32 of plate 22 until upper ends61 of the pawls move into alignment with the next adjacent holes 42.Then, upper ends 61 enter the aligned holes 42 thereabove and the pawlsforce frame 34 forwardly as disk 96 continues to rotate. The totaldistance traveled by frame 34 is such that the next adjacent die supporton the frame is vertically aligned with heater element 46. During theforward travel of the pawls, clamp finger 104 is elevated to allow frame34 to move over track 31. After the frame has been moved, the pawlsreturn to their starting positions. The timing diagram of FIG. 12illustrates the sequence of operation of apparatus 10. Curve A indicatesthe time in which Clamp 104 is up during a complete revolution of disk94. Curve B indicates frame movement during each revolution, and Curve Cindicates the time during which motor 102 is energized.

During a die bondingoperation, the heat radiated from heater element 46is intercepted by the sides and bottom of heat shield 150 and the heatisreflected toward the heater element. During this time, air rises inposts 156 by convection, thereby drawing air into the lower openings 168in bar 162 (FIG. 2a). The small amount of heat loss through the openends and the top of shield 150 is not sufficient to heat the surroundingstructure to any appreciable degree; thus, the operator of apparatus 10will not suffer discomfort if the hands or fingers contact the structureadjacent to element 46.

If apparatus 10 is to be used as a wire bonder. heater element 46 isreplaced by structure defining a frame support surface provided inopening 44 and a wire bonding tool is mounted in any suitable manner onsupport 12. Then, a frame having a plurality of chips previously bondedthereto can be incrementally moved over track 31 in the manner describedabove. Each time a chip is aligned centrally of opening 44, a wirebonding operation can occur wherein a plurality of wires are bonded tothe chip. In such a case, clamp finger 104 is used to clamp the frameagainst movement during the operation. It may be necessary to adjust thearc of movement of clamp finger 104 to. allow clearance of the chips asframe 34 carrying the chips is moved by the pawls. This adjustment ismade by moving rod 130 (FIG. 7) releasably secured at its lower end tobar 124.

Test probe unit 49 (FIGS. 10 and includes a bracket 200 secured byscrews 106 to swingable block 108; thus, bracket 200 replaces clampfinger 104 when apparatus 10 is to be used in testing integrated circuitchips or the like carried on frame 34. The height of bracket 200relative to upper surface 32 can be varied by adjusting the verticalposition of block 112 on side wall 16.

Bracket 200 has a pair of inclined recesses 204 extending thereinto froma pair of sides thereof. Each recess frictionally receives an insulatingblock 206 having a number of spaced, electrically isolated leads 208extending along the same, the lower ends of the leads projectingoutwardly from respective blocks and disposed for contactingcorresponding terminals on a chip to be tested. Recesses 204 areinclined oppositely relative to each other so that blocks 206 convergeas their lower ends are approached. A rigid support 210 in opening 44 isprovided to support frame 34 as leads 208 are disposed above and moveinto contact with the clip aligned with opening 44 during a testoperation.

Apparatus 10 is used in the manner described above to move frame 34incrementally relative to opening 44 when testprobe unit 49 is mountedas shown in FIGS. 10 and 10a. Leads 208 are coupled to test equipment(not shown) whereby, as motor 102 cycles, frame 34 is advancedincrementally and bracket 200 is elevated during frame movement becauseblock 108 pivots upwardly as the pawls reciprocate when the frame is ina new position, bracket 200 will have been lowered, causing the lowerends of leads 208 to move into contact with respect to terminals on thechip therebelow. In this way, each chip can be tested to determine itsquality before it is separated from the frame and packaged.

While pawls50 and 52 have been described as positioned to enter sideholes 42, it is possible that plate 22 could have slots 66 and 68 moretoward the center of track 31. In such a case, the pawls could enter thespaces between lateral strips 40 of frame 34, thus rendering apparatus10 suitable for use with frames having no side holes 42.

I claim:

1. Apparatus for incrementally advancing a die support frame having aplurality of openings therethrough comprising: a support; means on saidsupport for defining a track over which a die support frame can move; apawl for entering any one of said frame openings; means on one side ofthe track for mounting the pawl for pivotal movement in a planetransverse tosaid track; means coupled with said pawl for biasing thesame across the track; and means coupled with said mounting means forreciprocating the latter and thereby said pawl to cause the latter toenter a frame opening and to move the frame as the pawl is moved in onedirection and to cause the pawl to exit from a frame opening as the pawlmoves in the opposite directron.

2. Apparatus as set forth in claim 1, wherein said track defining meansincludes a generallyv horizontal plate having rail means at each sidethereof, said plate having a slot therethrough, said pawl mounting meansbeing below the plate, said pawl normally extending through the slot andprojecting above the plate.

3. Apparatus as set forth in claim 1, wherein said mounting meansincludes a longitudinally reciprocal rod extending longitudinally ofsaid track, afollower rigidly secured to said rod and extendinglaterally therefrom, and means pivotally mounting said pawl on saidfollower near the outer end thereof for movement about an axistransverse to said track and to said rod.

4. Apparatus as set forth in claim 3, wherein said reciprocating meansincludes an eccentric, means coupled to said eccentric for rotating thesame through a predetermined arc, and a coupling element interconnectingsaid eccentric and said rod.

5. Apparatus as set forth in claim 4, wherein is included a second rodparallel to the first-mentioned rod, said follower and said couplingelement being slidably engageable with and movable along said secondrod, whereby the latter serves as a guide therefor.

6. Apparatus for incrementally moving a die support frame provided witha plurality of uniformly spaced die supports and a plurality of openingstherethrough comprising: a support; means on the support for defining atrack along which the frame can be moved; a pawl receivable within eachopening of the frame; means-on the support for pivotally mounting thepawl for movement about a generally horizontal axis below and extendingtransversely to said track, said pawl being movable from a first,inclined position extending above the plane of the track to a second,generally horizontal position below said plane; means coupled with thepawl for biasing the same into said first position; and means coupledwith said pawl mounting means for reciprocating the latter along a pathsufficient to move the pawl from a first location along said track to asecond location and return, said pawl being engageable with the frameand pivoted from its first position to its second position when saidmounting means is shifted from said first location to said secondlocation. said bias means causing said pawl to return to its operativeposition and to enter the next adjacent frame opening when the mountingmeans moves into said second location, whereby said pawl will move theframe incrementally along said track as the mounting means returns tosaid first location from said second location.

7. Apparatus as set forth in claim 6, wherein said pawl has a generallyvertically disposed, frameengaging forward margin when the pawl is insaid first position, said bias means including a counterweightadjustably and eccentrically mounted on said pawl and engaging saidmounting means when the pawl is in said first position.

8. Apparatus as set forth in claim 6, wherein said track defining meansincludes a generally horizontal plate having a slot extendinglongitudinally of the path of the track, said pawl projecting upwardlythrough said slot when the pawl is in said first position and beingmovable longitudinally thereof as the pawl is reciprocated under theinfluence of said mounting means.

9. Apparatus as set forth in claim 8, wherein said slot is located atone side margin of the track.

10. Apparatus for handling a die support frame comprising: a support;means on the support for defining a track along which said frame canmove, s'aid means having a frame support surface; a clamp finger; meansadjustably mounted on said support for pivotally mounting said fingerthereon for movement about an axis extending longitudinally ofsaid trackand into and out of engagement with the frame on said track, said meansbeing adjustable; and means coupled'with said finger for pivoting thesame relative to said track.

11. Apparatus as set forth in claim 10, wherein said mounting means isadjustable in two mutually perpendicular directions.

12. Apparatus as set forth in claim 10, wherein said pivoting meansincludes a rod pivotally coupled at one end to said finger at a locationthereon in spaced relationship to said axis, and a rotatable barpivotally connected to the opposite end of the rod, said bar adapted tobe coupled to a source of power to cause the rod to be shifted andthereby cause the finger to be pivoted.

14. Apparatus as set forth in claim 13, wherein said bar has a bore,there being a member adjustablyv mounted in said bore, said memberhaving a conical recess for receiving the proximal end of said rod'.

1. Apparatus for incrementally advancing a die support frame having aplurality of openings therethrough comprising: a support; means on saidsupport for defining a track over which a die support frame can move; apawl for entering any one of said frame openings; means on one side ofthe track for mounting the pawl for pivotal movement in a planetransverse to said track; means coupled with said pawl for biasing thesame across the track; and means coupled with said mounting means forreciprocating the latter and thereby said pawl to cause the latter toenter a frame opening and to move the frame as the pawl is moved in onedirection and to cause the pawl to exit from a frame opening as the pawlmoves in the opposite direction.
 2. Apparatus as set forth in claim 1,wherein said track defining means includes a generally horizontal platehaving rail means at each side thereof, said plate having a slottherethrough, said pawl mounting means being below the plate, said pawlnormally extending through the slot and projecting above the plate. 3.Apparatus as set forth in claim 1, wherein said mounting means includesa longitudinally reciprocal rod extending longitudinally of said track,a follower rigidly secured to said rod and extending laterallytherefrom, and means pivotally mounting said pawl on said follower nearthe outer end thereof for movement about an axis transverse to saidtrack and to said rod.
 4. Apparatus as set forth in claim 3, whereinsaid reciprocating means includes an eccentric, means coupled to saideccentric for rotating the same through a predetermined arc, and acoupling element interconnecting said eccentric and said rod. 5.Apparatus as set forth in claim 4, wherein is included a second rodparallel to the first-mentioned rod, said follower and said couplingelement being slidably engageable with and movable along said secondrod, whereby the latter serves as a guide therefor.
 6. Apparatus forincrementally moving a die support frame provided with a plurality ofuniformly spaced die supports and a plurality of openings therethroughcomprising: a support; means on the support for defining a track alongwhich the frame can be moved; a pawl receivable within each opening ofthe frame; means on the support for pivotally mounting the pawl formovement about a generally horizontal axis below and extendingtransversely to said track, said pawl being movable from a first,inclined position extending above the plane of the track to a second,generally horizontal position below said plane; means coupled with thepawl for biasing the same into said first position; and means coupledwith said pawl mounting means for reciprocating the latter along a pathsufficient to move the pawl from a first location along said track to asecond location and return, said pawl being engageable with the frameand pivoted from its first position to its second position when saidmounting means is shifted from said first location to said secondlocation, said bias means causing said pawl to return to its operativeposition and to enter the next adjAcent frame opening when the mountingmeans moves into said second location, whereby said pawl will move theframe incrementally along said track as the mounting means returns tosaid first location from said second location.
 7. Apparatus as set forthin claim 6, wherein said pawl has a generally vertically disposed,frame-engaging forward margin when the pawl is in said first position,said bias means including a counterweight adjustably and eccentricallymounted on said pawl and engaging said mounting means when the pawl isin said first position.
 8. Apparatus as set forth in claim 6, whereinsaid track defining means includes a generally horizontal plate having aslot extending longitudinally of the path of the track, said pawlprojecting upwardly through said slot when the pawl is in said firstposition and being movable longitudinally thereof as the pawl isreciprocated under the influence of said mounting means.
 9. Apparatus asset forth in claim 8, wherein said slot is located at one side margin ofthe track.
 10. Apparatus for handling a die support frame comprising: asupport; means on the support for defining a track along which saidframe can move, said means having a frame support surface; a clampfinger; means adjustably mounted on said support for pivotally mountingsaid finger thereon for movement about an axis extending longitudinallyof said track and into and out of engagement with the frame on saidtrack, said means being adjustable; and means coupled with said fingerfor pivoting the same relative to said track.
 11. Apparatus as set forthin claim 10, wherein said mounting means is adjustable in two mutuallyperpendicular directions.
 12. Apparatus as set forth in claim 10,wherein said pivoting means includes a rod pivotally coupled at one endto said finger at a location thereon in spaced relationship to saidaxis, and a rotatable bar pivotally connected to the opposite end of therod, said bar adapted to be coupled to a source of power to cause therod to be shifted and thereby cause the finger to be pivoted. 13.Apparatus as set forth in claim 12, wherein said rod has a pair ofopposed convex ends, said finger and said bar having respective, conicalrecesses for pivotally receiving respective ends of said rod. 14.Apparatus as set forth in claim 13, wherein said bar has a bore, therebeing a member adjustably mounted in said bore, said member having aconical recess for receiving the proximal end of said rod.